Providing a driver with feedback typically provides a verbal or audio indication. For example, when a driver opens a car door with the headlights still on or the keys still in the ignition, many cars provide an audio alert (e.g., a series of beeps) to inform the driver that he might have forgotten to perform an action. Other systems may provide feedback to the driver when the vehicle is moving. For instance, the driver may be rapidly approaching another vehicle or be attempting to change lanes when another vehicle is located in his blind spot. Again, some systems provide an audio alert to warn the driver of the danger. The system may use sonification, which is the use of non-speech audio to convey information or perceptualize data, to provide the audio alert.
The types of audio alerts typically used, however, usually add to the driver cognitive load. That is, the driver has to process the audio alert and remember what the audio alert signifies. As such, the audio alert may be more distracting that it is helpful. For instance, the alert may cause the driver to over correct and place the driver in another dangerous situation. For some driver feedback systems, a more subtle or intuitive technique may be desired.